Anastomosis instrument and method

ABSTRACT

A surgical instrument for performing an anastomosis includes a housing having a proximal end and a distal end; a shaft extending from the housing distal end; and a disposable loading unit configured and dimensioned to retain a plurality of surgical fasteners, the disposable loading unit extending from the shaft and forming a juncture with the shaft, the disposable loading unit including: i) opposed split-sections pivotably connected to facilitate movement of the opposed split-sections between open and closed configurations, the opposed split sections being movable through a firing stroke from a first position to a second position and back to the first position to form a plurality of surgical fasteners; and ii) a pivot lockout member including a latch portion which extends between the opposed split-sections, the latch portion including a contact surface which interacts with a corresponding surface formed on at least one of the opposed split-sections to retain the opposed split-sections in the closed configuration, wherein upon return of the fastener pusher member to the first position from the second position, the pivot lockout member is displaced relative to the opposed split sections to an unlocked configuration.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a continuation of U.S. application Ser. No. 09/584,541 filedJun. 1, 2000 which is a continuation of 09/256,260 filed Feb. 23, 1999,now U.S. Pat. No. 6,083,234, which is a continuation-in-part of U.S.application Ser. No. 08/877,701, entitled “Singleshot AnastomosisInstrument With Detatchable Loading Unit and Method”, which was filedJun. 17, 1997 now U.S. Pat. No. 6,024,748 by Manzo et al., whichapplication is a continuation-in-part of U.S. application Ser. No.08/685,385, entitled “Anastomosis Instrument and Method”, filed Jul. 23,1996 by Hinchliffe et al., now U.S. Pat. No. 5,707,380, the entirecontents of both of these disclosures are hereby incorporated byreference. This application also claims priority from U.S. ProvisionalApplication Serial No. 60/102,326 which was filed on Sep. 28, 1998.

BACKGROUND

1. Technical Field

The present disclosure relates to a surgical instrument and method forperforming anastomosis of tubular body structures, and more particularlyto an instrument for performing vascular anastomoses.

2. Background of Related Art

Anastomoses of tubular body structures may be performed for a number ofdifferent procedures. One general example of an anastomosis is avascular anastomosis wherein two blood vessels are joined together topermit blood flow therebetween. A specific example of vascularanastomosis is an arteriovenous fistula (“A-V fistula”) which isperformed to facilitate hemodialysis for end stage kidney disease. Theprocedure usually consists of an end to side anastomosis joining anartery and a vein in the forearm, e.g., joining the radial artery end toside with the cephalic (radial) vein or the ulnar artery with thebasilic (ulnar) vein. It can also be performed in the leg, but usuallyafter all the arm sites have been exhausted. The A-V fistula allows asingle puncture at the dialysis unit for blood cleansing. The fistulaallows a greater flow and outflow rate through the dialyzer.

Another specific example of a vascular anastomosis is a coronary arterybypass graft (“CABG”). Coronary artery disease is often characterized bylesions or occlusions in the coronary arteries which may result ininadequate blood flow to the myocardium, or myocardial ischemia, whichis typically responsible for such complications as angina pectoris,necrosis of cardiac tissue (myocardial infarction), and sudden death. Insome cases, coronary artery disease may be treated by the use of drugsand by modifications in behavior and diet. In other cases, dilatation ofcoronary arteries may be achieved by such procedures as angioplasty,laser ablation, atherectomy, catheterization, and intravascular stents.

For certain patients, a CABG procedure is the preferred form oftreatment to relieve symptoms and often increase life expectancy. A CABGprocedure consists of direct anastomosis of a vessel segment to one ormore of the coronary arteries. For example, a reversed segment of thesaphenous vein may be grafted at one end to the ascending aorta as anarterial blood source and at the other end to a coronary artery at apoint beyond the arterial occlusion. Alternatively, the internal mammaryartery (IMA) is located in the thoracic cavity adjacent the sternum andis likewise suitable for grafting to a coronary artery, such as the leftanterior descending artery (LAD).

The performance of a CABG procedure typically requires access to theheart, blood vessels and associated tissue. Access to the patient'sthoracic cavity may be achieved in an open procedure by making a largelongitudinal incision in the chest. This procedure, referred to as amedian sternotomy, requires a saw or other cutting instrument to cut thesternum and allow two opposing halves of the rib cages to be spreadapart. U.S. Pat. No. 5,025,779 to Bugge discloses a retractor which isdesigned to grip opposite sternum halves and spread the thoracic cavityapart. The large opening which is created by this technique enables thesurgeon to directly visualize the surgical site and perform procedureson the affected organs. However, such procedures that involve largeincisions and substantial displacement of the rib cage are oftentraumatic to the patient with significant attendant risks. The recoveryperiod may be extensive and is often painful. Furthermore, patients forwhom coronary surgery is indicated may need to forego such surgery dueto the risks involved with gaining access to the heart.

U.S. Pat. No. 5,503,617 to Jako discloses a retractor configured to beheld by the surgeon for use in vascular or cardiac surgery to retractand hold ribs apart to allow access to the heart or a lung through anoperating “window”. The retractor includes a rigid frame and atranslation frame slidably connected to the rigid frame. Lower and upperblades are rotatably mounted to the rigid frame and the translationframe respectively. The “window” approach enables the surgeon to gainaccess through a smaller incision and with less displacement of theribs, and consequently, less trauma to the patient.

Once access to the thoracic cavity has been achieved, surgery on theheart may be performed. Such procedures typically require that the heartbeat be arrested while maintaining circulation throughout the rest ofthe body. Cardioplegic fluid, such as potassium chloride (KCl) isdelivered to the blood vessels of the heart to paralyze the myocardium.As disclosed in WO 95/15715 to Sterman et al. for example, cardioplegicfluid is infused into the myocardium through the coronary arteries by acatheter inserted into the ascending aorta. Alternatively, cardioplegicfluid is infused through the coronary veins in a retrograde manner by acatheter positioned in the interior jugular vein accessed at thepatient's neck. Such procedures require the introduction of multiplecatheters into the blood vessels adjacent the heart, which iscomplicated procedure requiring that the desired vessels be properlylocated and accessed. The progression of the guide wires and cathetersmust be closely monitored to determine proper placement. Furthermore,the introduction of catheters forms punctures in the blood vessels thatmust be subsequently closed, and there is an increased risk of trauma tothe interior walls of the vessels in which the catheters must pass.

Alternatively, the CABG procedure may be performed while the heart ispermitted to beat. Such a procedure is now commonly referred to asminimally invasive direct coronary artery bypass (MIDCAB). A surgicalinstrument is used to stabilize the heart and restrict blood flowthrough the coronary artery during the graft procedure. Special caremust be given to procedures performed on a beating heart, e.g.synchronizing procedures to occur at certain stages in the cardiaccycle, such as between heartbeats.

To perform a CABG procedure, the harvested vessel segment, such as theIMA, is grafted to the coronary artery by end-to-side anastomosis.Typically, sutures are used to graft the vessel segments. However,conventional suturing is complicated by the use of minimally invasiveprocedures, such as the window approach. Limited access and reducedvisibility may impede the surgeon's ability to manually apply sutures toa graft. Additionally, it is difficult and time consuming to manuallysuture if the CABG procedure is being performed while the heart isbeating as the suturing must be synchronized with the heart beat.

The process of manually suturing the harvested vessel segment to acoronary artery is time consuming and requires a great deal of skill onthe part of the surgeon. The resulting sutured anastomosis will also bedependent on the skills of the surgeon. In minimally invasive proceduressuch as in MIDCAB, the ability to suture is even more complicated due tolimited maneuverability and reduced visibility. U.S. Pat. No. 5,707,380to which issued on Jan. 3, 1998 to Hinchliffe et al., the entirecontents of which are hereby incorporated by reference, discloses anapparatus and a procedure that enables the remote anastomosis withoutpiercing of vessels during both conventional and minimally invasiveprocedures. A continuing need exists, however, for improved surgicalinstruments and methods for performing remote anastomoses during bothconventional and minimally invasive procedures.

SUMMARY

The present disclosure provides a surgical instrument for performing ananastomosis, which includes a housing having a proximal end and a distalend; a shaft extending from the housing distal end; and a disposableloading unit configured and dimensioned to retain a plurality ofsurgical fasteners, the disposable loading unit extending from the shaftand forming a juncture with the shaft, the disposable loading unitincluding: i) opposed split-sections pivotably connected to facilitatemovement of the opposed split-sections between open and closedconfigurations, the opposed split sections being movable through afiring stroke from a first position to a second position and back to thefirst position to form a plurality of surgical fasteners; and ii) apivot lockout member including a latch portion which extends between theopposed split-sections, the latch portion including a contact surfacewhich interacts with a corresponding surface formed on at least one ofthe opposed split-sections to retain the opposed split-sections in theclosed configuration, wherein upon return of the fastener pusher memberto the first position from the second position, the pivot lockout memberis displaced relative to the opposed split sections to an unlockedconfiguration.

A lock member is disposed relative to the juncture of the disposableloading unit and the shaft, the lock member operable from the housingand movable between an unlocked position wherein the disposable loadingunit is unsecured relative to the shaft and a locked position whereinthe disposable loading unit is secured relative to the shaft. The lockmember may further be biased towards the locked position.

An actuator lever is disposed on the housing and operatively associatedwith the opposed split sections such that movement of the actuator leverfrom an initial position to a secondary position effects movement of theopposed split sections being from the first position to the secondposition to effect deformation of the plurality of surgical fasteners.

A firing safety assembly is provided which operatively interacts withthe actuator lever to prevent unintended movement of the actuator leverfrom the initial position to the secondary position. The firing safetyassembly is normally biased towards a locked out configuration.

In a particular aspect of the present disclosure, the shaft and thedisposable loading unit each define respective central longitudinal axeswhich are substantially axially aligned with each other.

In a further embodiment of the present disclosure, a surgical instrumentfor performing an anastomosis is provided which includes a housinghaving a proximal end and a distal end, a shaft extending from thehousing distal end; a disposable loading unit rotatably and detachablyextending from the shaft and forming a juncture with the shaft, thedisposable loading unit including: i) a fastener support memberconfigured and dimensioned to support a plurality of surgical fastenersin a predetermined array of a generally close-ended geometricconfiguration; and ii) a fastener pusher member disposed adjacent thefastener support member, the fastener pusher member being movable from afirst position relative to the plurality of surgical fasteners to asecond position relative to the plurality of surgical fasteners so as todeform the plurality of surgical fasteners to a tissue grippingorientation; and a lock member disposed relative to the juncture of thedisposable loading unit and the shaft, the lock member operable from thehousing and movable between an unlocked position wherein the disposableloading unit is unsecured relative to the shaft and a locked positionwherein the disposable loading unit is secured relative to the shaft.

An actuator lever is disposed on the housing and operatively associatedwith the fastener pusher member such that movement of the actuator leverfrom an initial position to a secondary position effects movement of thefastener pusher member from the first position to the second position toeffect deformation of the plurality of surgical fasteners.

An actuator rod is also provided which is connected to the actuatorlever and wherein the disposable loading unit further includes anactuator member which interacts with the actuator lever to effectmovement of the fastener pusher member from the first position to thesecond position to effect deformation of the surgical fasteners.

A firing safety assembly is also provided which operatively interactswith the actuator lever to prevent unintended movement of the actuatorlever from the initial position to the secondary position. The firingsafety assembly may normally be biased towards a locked outconfiguration.

In a particular aspect of the present disclosure, the shaft and thefastener pusher member each define respective central longitudinal axeswhich are substantially axially aligned with each other.

In another aspect of the present disclosure, the fastener support memberand the fastener pusher member are each formed of respective opposingsplit-sections, at least two of the split-sections being pivotablyconnected to facilitate movement of the opposed split-sections betweenopen and closed configurations. A pivot lockout member is also providedwhich extends between the opposed split-sections and includes a contactsurface which interacts with a corresponding surface formed on at leastone of the opposed split-sections to retain the opposed split-sectionsin the closed configuration. Optionally, the fastener pusher member isbiased to return to the first position after movement to the secondposition. A particular feature of the present disclosure is that uponreturn of the fastener pusher member to the first position from thesecond position, the pivot lockout member is displaced to an unlockedconfiguration.

In a further alternative embodiment, the present disclosure alsoprovides a disposable loading unit for a surgical anastomosisinstrument, which includes an elongated fastener support member defininga pathway extending at least partially therethrough and including afirst opening at a distal end thereof and a second opening spaced fromthe distal end and in communication with the pathway, the second openingconfigured and dimensioned to receive a tubular vessel therethrough suchthat the tubular vessel can pass through the pathway and extend outwardfrom the first opening at the distal end, the fastener support memberfurther including a plurality of spaced apart retention slots definedtherein, each retention slot being adapted to support a respectivesurgical fastener of a plurality of surgical fasteners; a fastenerpusher member disposed adjacent the fastener support member, thefastener pusher member movable from a first position relative to theplurality of surgical fasteners to a second position relative to theplurality of surgical fasteners so as to deform the plurality ofsurgical fasteners; an actuator operatively associated with the fastenerpusher member to effect movement of the fastener pusher member from thefirst position to the second position; and a mounting hub disposedadjacent the actuator and defining an access opening, such that aportion of the actuator is accessible through the access opening, themounting hub being configured and dimensioned to be removably androtatably attached to a distal portion of the surgical instrumentthereby facilitating removable attachment of the disposable loading unitto the surgical instrument.

In one aspect of the embodiment, the fastener support member and thefastener pusher member are each formed of respective opposingsplit-sections, at least two of the split-sections being pivotablyconnected to facilitate movement of the opposed split-sections betweenopen and closed configurations. A further feature of the embodiment is apivot lockout member which extends between the opposed split-sectionsand includes a contact surface which interacts with a correspondingsurface formed on at least one of the opposed split-sections to retainthe opposed split-sections in the closed configuration. In a furtheraspect of the embodiment, the fastener pusher member is biased to returnto the first position after movement to the second position. In afurther unique feature of the present disclosure, upon return of thefastener pusher member to the first position from the second position,the pivot lockout member is displaced to an unlocked configuration.

The present disclosure also provides a method of performing a vascularanastomosis which includes the steps of providing a disposable loadingunit having a fastener support member defining a passage therethroughfor reception of a first vessel, a plurality of surgical fastenerssupported by the fastener support at a distal end thereof; positioningan end of the first vessel through the passage and everting the end ofthe vessel over the distal end of the fastener support adjacent theplurality of surgical fasteners; engaging the first vessel with thesurgical fasteners; inserting the distal edge of the fastener supportinto an opening in a side wall of a second vessel; engaging the sidewall of the second vessel with the surgical fasteners adjacent theopening; connecting the disposable loading unit to an actuator handleassembly after step e) such that the disposable loading unit isrotatable with respect to the actuator handle assembly; and deformingthe legs of each surgical fastener by actuation of the actuator handleassembly to secure the first and second vessels together in fluidcommunication with each other.

In a further aspect of the presently disclosed method, an additionalstep is provided of removing the first vessel from the disposableloading unit by opening a split-section of the disposable loading unit.

BRIEF DESCRIPTION OF THE DRAWINGS

An illustrative embodiment of the subject surgical instrument and methodare described herein with reference to the drawings wherein:

FIG. 1 is a perspective view of a surgical instrument constructed inaccordance with a preferred embodiment of the present disclosure;

FIG. 2 is a perspective view of a disposable loading unit constructed inaccordance with a preferred embodiment of the present disclosure;

FIG.3 is a perspective view of the disposable loading unit of FIG. 2 asseen from a reverse angle;

FIG. 4 is a perspective view the disposable loading unit embodiment ofFIG. 2 shown with parts separated;

FIG. 5 is a perspective view of a fastener pusher half-section and ahinge lock the embodiment of the disposable loading unit of FIG. 2;

FIG. 6 is a side view of the disposable loading unit of the embodimentof FIG. 2;

FIG. 7 is a perspective view of the disposable loading unit of theembodiment of FIG. 2 showing a hinge lock and a cover plate separated;

FIG. 8 is a horizontal cross-sectional view of the disposable loadingunit shown greatly enlarged for clarity;

FIG. 9 is a perspective view of a handle/actuator assembly of thesurgical instrument with parts separated;

FIG. 10 is a perspective view of the handle/actuator assembly of FIG. 9shown with parts separated;

FIG. 11 is an enlarged view of the distal end of a disposable loadingunit holding tube;

FIG. 12 is a horizontal cross section of the handle/actuator assembly;

FIG. 13 is a view showing an operating “window” with the patient's heartexposed;

FIG. 14 is a perspective view of a disposable loading unit with a firstvessel inserted therethrough;

FIG. 15 is a perspective view of the disposable loading unit shown inreverse angle from that of FIG. 14, which shows the vascular tissueeverted over a plurality of surgical fasteners;

FIG. 16 is a horizontal cross-sectional view of the disposable loadingunit of FIG. 15;

FIG. 17 is a perspective view showing insertion of the disposableloading unit and everted vascular tissue through a second vessel;

FIG. 18 is a view similar to FIG. 17, which shows full insertion of thedistal end of the disposable loading unit with the everted vasculartissue through an incision formed in the second vessel;

FIG. 19 is a horizontal cross-sectional view of the inserted disposableloading unit of FIG. 18;

FIG. 20 is a horizontal cross-sectional view of the handle/actuatorassembly;

FIG. 21 is a partial horizontal cross-sectional view showing a lockingmechanism to secure the disposable loading unit to the handle/actuatorassembly;

FIG. 22 is an enlarged view isolating on the safety firing lockoutmember of the handle/actuator assembly;

FIG. 23 is a view similar to FIG. 22, which shows operation of thesafety firing lockout;

FIG. 24 is a horizontal cross-sectional view of the handle/actuatorassembly, which shows the firing sequence of the handle/actuatorassembly;

FIG. 25 is an enlarged horizontal cross-sectional view of the distal endof the handle/actuator assembly and the disposable loading unit, whichshows the deformation of the surgical fasteners;

FIG. 26 is a side view showing operation of the disposable loading unit;

FIG. 27 is a view similar to FIG. .26, which shows retraction of apusher member of the disposable loading unit after deformation of thesurgical fasteners;

FIG. 28 is a horizontal cross-sectional view, which shows retraction ofan actuator rod of the handle/actuator assembly and lockout of a hingelock on the disposable loading unit;

FIG. 29 is an enlarged view of the indicated area of detail of FIG. 28;

FIG. 30 is a perspective view of the distal end of the surgicalinstrument showing the opening of the disposable loading unit;

FIG. 31 is a view showing the completed anastomosis;

FIG. 31A is a view showing an alternative anastomosis site for aprocedure known as an A-V fistula;

FIG. 32 is a perspective view of an alternative embodiment of a safetyfiring lockout member of the handle/actuator assembly;

FIG. 33 is a perspective view of a safety release slide of theembodiment of FIG. 32;

FIG. 33A is a perspective view showing the bottom of the safety releaseslide of FIG. 33;

FIG. 34 is a perspective view of a lockout spring of the safety firinglockout of FIG. 32;

FIG. 35 is a perspective view of an actuator rod of the embodiment ofFIG. 32;

FIG. 36 is a partial cross-sectional view illustrating the initiallockout configuration of the safety firing lock-out mechanism of FIG.32;

FIG. 37 is a view similar to FIG. 36, which illustrates an operationalsequence of the safety firing lockout mechanism;

FIG. 38 is a view similar to FIG. 36 which illustrates an operationalsequence of the safety firing lockout mechanism; and

FIG. 39 is a view similar to FIG. 36 which illustrates a furtheroperational sequential view of the safety firing lockout mechanism.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Preferred embodiments of the surgical instrument and method disclosedherein will be described in terms of a minimally invasive directcoronary artery bypass (MIDCAB) procedure wherein a vascular anastomosisis created by joining a section of a harvested vessel, e.g., theinternal memory artery (IMA) to bypass an occlusion in a coronaryartery, e.g., the left anterior descending artery (LAD). However, thepresently disclosed surgical anastomosis instrument may also be utilizedin performing anastomosis of other tubular luminal body structures. Forexample, the presently disclosed surgical anastomosis instrument mayalso be utilized to perform an A-V fistula to facilitate hemodialysis.This procedure consists of an end-to-side anastomosis joining an arteryand a vein in the forearm or near the elbow. The A-V fistula allows asingle puncture at the dialysis unit for blood cleansing.

Referring now in detail to the drawing figures in which like referencenumerals identify similar or identical elements, one embodiment of thepresent disclosure is illustrated generally in FIG. 1 and is designatedtherein as surgical instrument 100. Briefly, surgical instrument 100includes a handle/actuator assembly 110 having a disposable loading unit112 which is removably and rotatably attached to the handle/actuatorassembly 110 by way of intermediate section 114 which extends from adistal end of housing/actuator assembly 110.

Referring now to FIGS. 2-8, disposable loading unit 112 includes atwo-part fastener support member made up of split half-sections 116 aand 116 b which form a hinge and are connected to each other by hingepin 118. Split half-section 116 a includes an actuator barrel 120 whichforms a bore that opens at a proximal end. Actuator barrel 120 includesopposed longitudinal slots 122 and 124 to facilitate operation of anactuator member 126 which is slidably mounted in actuator barrel 120.Actuation member 126 is spring biased to a proximal-most orientation bya coil spring 128. Actuator 126 is further retained within actuatorbarrel 120 by a lock ring 130 which includes an annular groove 132defined by proximal and distal flanges 134 and 136, respectively. Eachof the proximal and distal flanges 134 and 136 include a pair of opposedslotted portions which are aligned to facilitate locking of ring 130anterior portion of a mounting hub 138. For example, by way of passinglock ring 130 over opposed extended tabs 140 and 142, as best seen inFIG. 8, at the rotating lock ring 130 one quarter turn such that thepairs of opposed slots formed in proximal flange and distal flange 134and 136, respectively, are rotated 90° with respect to tabs 140 and 142.Lock ring 130 is biased against the distal facing surfaces of extendedtabs 140 and 142 by the force of compressed coil spring 128 which isdisposed in the bore formed longitudinally within actuator 126. Inparticular, a shoulder portion 144 of actuator 126 is biased against anannular lip 146 (FIG. 4) which is formed on the distal facing surface oflock ring 130. Actuator member 126 further includes a pair of opposedtransversely extending slots 148 and 150 formed on the outer surfacethereof which, as will be described in further detail herein, provide anengagement surface for a fastener pusher member.

Split half-sections 116 a and 116 b of the fastener support member areprovided with fastener retaining sections 152 and 154. Each of fastenerretaining sections 152 and 154 are provided with a plurality oflongitudinal channels 156 which are configured and dimensioned tosupport a “C”-shaped surgical fastener or clip 158 therein by, forexample, friction or partial compression of clips 158. Fastenerretaining sections 152 and 154 are preferably arranged such thatlongitudinal channels 156 form an eccentric array radially about theouter surface of fastener support member 116. This arrangementfacilitates the efficacious formation of an angled connection or fistulabetween the vessels to be joined. Such a connection facilitates betterfluid flow through the anastomotic site.

A fastener pusher member 160 is provided to facilitate deformation ofclips 158 during firing of the instrument. Fastener pusher member 160 ismade up of split half-sections 160 a and 160 b which are secured tosplit half-sections 116 a and 116 b, respectively, by way of mountingplates 162 and 164 and screws 166 which are threaded into threaded holesformed in receiving posts 168, 170; and 172, 174 disposed on splithalf-sections 116 a and 116 b, respectively. Mounting plates 162 and 164are attached to split half-sections 116 a and 116 b in a manner topermit longitudinal sliding movement of split half-sections 160 a and160 b of fastener pusher member 160 relative to fastener support member116. This sliding movement is facilitated by longitudinally alignedslots 176, 178; and 180, 182 which are provided on split half-sections160 a and 160 b, respectively.

Split half-sections 160 a and 160 b are further provided with moldedsurfaces such as protrusions 184 and depressions 186 as shown on splithalf-section 160 a which interfit with corresponding protrusions anddepressions formed on split half-section 160 a so as to prevent relativelongitudinal movement of split half-sections 160 a and 160 b. Steppedcamming or pusher surfaces 188 are formed on the distal ends of each ofsplit half-sections 160 a and 160 b and serve to cam a proximallyoriented portion of clips 158 towards a distal oriented portion of clips158. This motion effects deformation of the clips upon firing ofsurgical instrument 100.

Finally, a hinge lock 190 is mounted between mounting plate 162 andsplit half-section 160 b. Hinge lock 190 is provided with latch portions192 and 194 which extend transversely across one side of disposableloading unit 112 to latch onto raised correspondingly shaped surfaces196 and 198, respectively, formed on the outer surface of splithalf-section 160 a. Hinge lock 190 is further provided with a pair oflongitudinally oriented slots 200 and 202 which are radially alignedwith slots 180 and 182 of split half-section 160 b to facilitaterelative longitudinal movement of hinge lock 190 with respect to bothsplit half-section 160 b and split half-section 116 a. A flexible returnlockout tab 204 extends proximally from the distal end of slot 202 andis cantilevered outwardly away from a plane defined by slots 202 and 204such that it is positioned in a tab receiving recess 206 formed on theinner surface of mounting plate 162 when the DLU 112 is in a pre-firedcondition. A lockout slot 208 is formed longitudinally aligned with tabreceiving recess 206 and spaced distally therefrom such that upon distalmovement of hinge lock 190 (when split half-section 160 b is moveddistally), return lockout tab will be deflected to a flattened conditionand will extend into lockout slot 208 in order to prevent subsequentproximal movement of hinge lock upon proximal movement of split half2section 160 b after firing of surgical instrument 100.

In this manner, after firing of surgical instrument 100, latch portions192 and 194 of hinge lock 190 will remain distal relative to raisedsurfaces 196 and 198 of split half-section of 160 a by permitting thesplit half-sectioned DLU 112 to be opened by pivoting splithalf-sections 116 b and 160 a away from split half-sections 116 a and160 b to facilitate removal of the vessel segment from within the vesselpathway formed through the distal end of DLU 112 and out through alateral opening 210 formed by aligned molded recesses formed in each ofsplit half-sections 116 a, 116 b; and 160 a and 160 b of fastenersupport member 116 and fastener pusher member 160, respectively.

Referring now to FIGS. 9-12, the handle/actuator assembly 110 ofsurgical instrument 100 will now be described in detail. Handle/actuatorassembly 110 includes a housing formed of half-sections 212 a and 212 bwhich are preferably molded to have recessed inner surfaces and contoursformed therein to house the various components which are containedwithin handle/actuator assembly 110. In particular, handle/actuatorassembly 110 includes a DLU mounting assembly which facilitatesdetachable mounting of a DLU 112 to the distal end of handle/actuatorassembly 110. The DLU mounting assembly includes an elongated holdingtube 214 which is held longitudinally and rotationally fixed relative tohousing half-sections 212 a and 212 b. This mounting arrangement may beaccomplished for example, by way of an annular flange 216 formedadjacent the proximal end of holding tube 214 being held within anannular groove defined by partition wall segments 218 and 220 formed ineach of housing half-sections 212 a and 212 b. Holding tube 214 isfurther prevented from rotational movement by way of flattened sidewallportions 222 formed on opposing sides of holding tube 214 being retainedwithin and abutting flat surfaces 224 and 226 formed long partition wallsegments 218 and 220, respectively, in each of housing half-sections 212a and 212 b. DLU locking tube 215 is secured within a collar 228 formedon slide 217. Tube 215 may be secured in slide 217 by any suitablemeans, for example, friction fitting bonding, adhesives, or the like.Coil spring 219 is interposed in housing half-sections 212 a and 212 bbetween partitioned segments 218 and the proximal end surface of collar228. In this manner, locking tube 215 is biased in a distal-mostposition which corresponds to a locked position to retain DLU 112 on thedistal end of surgical instrument 100. The distal end of DLU holdingtube 214 is provided with a semi-annular groove 230 which is dimensionedto receive mounting hub 138 formed at the proximal end of DLU 112.Semi-annular groove 230 is dimensioned to permit DLU mounting hub 138 torotate within the groove.

Handle and actuator assembly 110 further includes a firing assemblywhich facilitates movement of actuator 126 housed within the actuatorbarrel 120. In the embodiment illustrated in FIGS. 9-15, the firingassembly is a linkage mechanism which imparts reciprocating longitudinalmovement in an actuator rod by way of movement of an actuator lever.However, it is within the scope of the present disclosure that theactuator rod may be reciprocatingly moved by any suitable known methods.The firing assembly basically includes an actuator rod 232 which isconnected to an actuator lever 234 by way of links 236 pivotallyattached at either end to actuator rod 232 and actuator lever 234,respectively. Actuator rod 232 is slidably disposed within alongitudinal bore formed through DLU holding tube 214. Actuator rod 232is biased in a proximal-most position by way of a torsion spring 238being mounted on a post 240 formed near the proximal end of housinghalfsection 212 b. Extended legs 238 a and 238 b are provided on torsionspring 238 to bias actuator lever 234 upwardly away from housinghalf-sections 212 a and 212 b thereby pulling actuator rod 232 towardits proximal-most position as determined by the abutment of annularshoulder 242 against partition 244 formed in each of housinghalf-sections 212 a and 212 b. To facilitate comfort and ease ofoperation for the user, a cover 246 is secured over actuator lever 234and is independently pivotally mounted to housing half-sections 212 aand 212 b. Cover 246 is provided with an ergonomic surface 248 which iscontoured and configured to be comfortably actuated by the thumb of auser when handle and actuator assembly 210 is held in the palm of theuser's hand.

A firing safety mechanism is also provided to prevent premature firingof surgical instrument 100. In the illustrated embodiment, the firingsafety assembly includes an inverted leaf spring 250 having a cut-outportion 252 formed therein which biases against a shoulder 254 formed onactuator rod 232. Spring 250 is further provided with a hook portion 256formed at the proximal end thereof which latches onto a protrudingsurface 258 formed in housing half-sections 212 a and 212 b. In thismanner, spring 250 prevents distal movement of actuator rod 232 when thesafety mechanism is armed. A safety release slide 260 which includes anupwardly extending contact surface which is exposed from the uppersurface of housing half-sections 212 a and 212 b to permit the user tooperate the slide and forms a clevis on a lower portion thereof whichreceives a flattened section 266 of actuator rod 332. Safety releaseslide 260 is further provided with a camming surface 268 along the loweredge thereof which cams the spring 250 out of contact with shoulder 254upon proximal movement of safety release slide 260.

In use, as shown in FIGS. 13-31, surgical instrument 100 facilitates theperformance of a vascular anastomosis without the need for manualsuturing of the vessels. The method and usage described herein will beaddressed in terms of minimally invasive vascular anastomosis performedon a beating heart such as in a MIDCAB procedure. However, the presentlydisclosed surgical instrument may also be used in performing anastomosesof other tubular or luminal body structures without departing from thescope of the present disclosure. For example, surgical instrument 100may be used in conventional open CABG procedures using a mediansternotomy or other large incision without stopping the heart.Alternatively, the thoracic “window” procedure may be used to achieveaccess to the heart. The “window” approach involves a smaller incisionand less displacement of the ribs, and therefore is less traumatic tothe patient. For this approach, conventional surgical techniques areused to determine the location of the incision to access the chestcavity.

In particular, a surgical retractor assembly may be used to separate theribs at the site of the incision as shown in FIG. 13. Specifically, abase 270 is placed on the chest of the patient with the central openingdefined by the base being positioned over the operative site. Retractorassemblies 272 are mounted to the base at various locations. Each ofretractor assemblies 272 includes a blade having a hook to engage eithera rib or the sternum therewith. The retractor assemblies are mounted andused to retract ribs until a sufficiently large opening in the chestcavity is defined to provide direct access to the heart. For example,the sternum and the fourth and fifth ribs can be split apart to create awindow. Other configurations of spreading the ribs and/or selectivelycutting individual ribs away from the sternum may also be utilized for aparticular procedure. Once the desired access to the heart is achieved,the graft vessel, e.g., the internal memory artery (IMA) is dissectedfrom the surrounding cartilage and muscle, in a free end of the vesselis exposed. The occluded coronary artery, e.g., the left anteriordescending artery (LAD), is then prepared for receiving the IMA graft.The heart is positioned in the desired orientation either by tractionsutures passing through the pericardium or by manipulation with heartmanipulation instruments which are held by the surgical personnel orclamped in a fixed orientation to a base such as the retractor assemblybase. One such heart manipulating instrument is available from UnitedStates Surgical Corporation of Norwalk, Conn. Blood flow through the LADcan be restricted by cardiopulmonary bypass and pericardial cooling.Alternatively, a damping instrument may be applied directly on the LADto restrict blood flow and reduce movement of the heart near the LAD.Such a heart stabilizing instrument is also available from United StatesSurgical Corporation of Norwalk, Conn.

Referring to FIG. 14, the free end of the IMA is inserted throughlateral opening 210 of DLU 112 and passed out the distal end opening ofthe DLU. The free end of the IMA is then everted over the distal end ofthe DLU such that the end of the IMA is retained by the distal endoriented portions of clips 158 as best shown in FIG. 15 and FIG. 16.Everting of the tissue may be achieved by any suitable known techniquessuch as y using graspers. With the IMA loaded in DLU 112, the DLU ismanipulated preferably detached from the handle and actuator assembly110 in approximation to an incision “I” formed in the LAD, as shown inFIG. 17. Referring to FIGS. 18 and 19, the DLU with the everted IMA isinserted into the incision “I” of the LAD such that the walls of the LADsurrounding the incision are retained between the everted end of the IMAand the proximal ends of clips 158, as shown in FIG. 19. As previouslynoted, the distal end of DLU 112 is configured with an angle relative toa transverse plane of the DLU in order to optimize the anastomosis andto facilitate optimal blood flow across the graft site from the IMA tothe LAD. This junction creates “heel” and “toe” portions in which anacute or obtuse angle between the vessels is defined.

Once DLU 112 with the everted IMA has been successfully inserted throughthe incision of the LAD, the surgeon may then attach the handle/actuatorassembly 110 to DLU 112 as shown in FIGS. 20 and 21. In particular, theDLU lock slide 217 is moved proximally as indicated by arrow “A” inorder to retract locking tube 215 and thereby expose the distal end ofDLU holding tube 214, and in particular, semi annular groove 230. DLU112 is inserted on the distal end of the handle and actuator assembly110 by placing mounting hub 138 within semi-annular groove 230 andreleasing the force applied on DLU lock slide 217 as indicated by arrow“B” in FIG. 21, to permit coil spring 219 to return lock slide 217 andlocking tube 215 to their distal-most orientations thereby securing theDLU in place.

Referring to FIGS. 22 and 23, when the surgeon is ready to complete theanastombsis, the safety release slide 260 is moved proximally asindicated by arrow “C” in FIG. 23 thereby causing camming surface 268 tocam spring 250 downwardly away from shoulder 254 as indicated by arrow“D”. Thereafter, the surgeon may depress cover 246 towards handlehalf-sections 212 a and 212 b , as indicated by arrow “E” in FIG. 24,causing actuator rod 232 to drive actuator 126 of DLU 112 distally asindicated by arrow “F”, thereby moving pusher member split half-sections160 and 160 b distally to deform clips 158 as shown in FIGS. 25 and 26.

As best illustrated in FIG. 24, one particularly advantageous feature ofthe presently disclosed surgical instrument is that upon actuation ofhandle/actuator assembly 110, safety release slide 260 is urged backinto its initial locked orientation by way of annular flange 216 ofactuator rod 232 pushing the lower portion of safety release slide 260during the distal movement of actuator rod 232. In this manner, uponrelease of cover handle 246, the potential energy created by thecompression of torsion spring 238 will cause actuator rod 232 to bepulled back proximally thereby engaging shoulder 254 with cutout 252 ofspring 250. This will serve to prevent accidental re-firing action ofsurgical instrument 100.

Referring to FIGS. 26-30, a further uniquely advantageous feature ofsurgical instrument 100 is hinge lock 190 and its operation. Upon firingof surgical instrument 100, return lockout tab 204 of hinge lock 190,which extended into lockout slot 208 during distal movement of hingelock 190 with split half-sections 160 and 160 b, serves to retain hingelock 190 distal of its original seated location in tab receiving recess206. By retaining hinge lock 190 at this position, latch portions 192and 194 are released from raised surfaces 196 and 198 of splithalf-section 160 a of the pusher member. In this manner, splithalf-section 116 b and 160 a may be pivoted away from splithalf-sections 116 a and 160 b as shown in FIG. 30 to permit the removalof the IMA from within the pathway of the DLU thereby completing thevascular anastomosis as shown in FIG. 31.

Referring to FIG. 31A, a portion of the vascular anatomy of an arm whichmay be an alternative utilized anastomosis site as illustrated whereininstead of joining the IMA to the LAD in a bypass procedure, an A-Vfistula is performed utilizing surgical instrument 100 to join theradial artery end-to-side with the cephalic vein (sometimes called theradial vein). Other A-V fistulas which may also be achieved utilizingsurgical instrument 100 include joining the ulnar artery end-to-sidewith the basilic vein (sometimes called the ulnar vein). Such A-Vfistulas are performed to facilitate hemodialysis for end stage kidneydisease to allow a single puncture at the dialysis unit for bloodcleansing. The fistula allows a greater flow rate through the dialyzer(not shown).

Referring to FIGS. 32-39, an alternative embodiment of the firing safetymechanism illustrated in FIGS. 22-24 is illustrated which also preventsthe unintended firing of surgical instrument 100. The firing safetymechanism includes a lock spring 350 and a safety release slide 360.Referring to FIGS. 33 and 33A, safety release slide 360 includes a pairof camming surfaces 360 a and 360 b which interact with cam followersurfaces 350 d and 350 e. Lock spring 350, as best illustrated in FIG.34, includes a body portion 350 a that defines a yoke, a pair a leafspring portions 350 b and 350 c, and a pair of cam follower surfaces 350d and 350 e formed along a top portion thereof. An actuator rod 332,FIG. 35, is configured and dimensioned to pass through yoke portion 350a of lock spring 350.

In the initial (pre-fired) configuration, as shown in FIG. 36, safetyrelease slide 360 is disposed above lock spring 350 such that cammingsurfaces 360 a and 360 b contact cam following surfaces 350 e and 350 e,respectively, when safety release slide 360 is in the distal-mostposition. In this orientation, leaf spring portions 350 b and 350 cserve to bias lock spring 350 upwardly within the instrument housing sothat a shoulder portion 332 a of actuator rod 332 abuts against aproximal facing lower surface 350 f, as shown in FIG. 36, to preventfiring of the instrument.

When the surgeon desires to fire the instrument, safety release slide360 is moved proximally as indicated by arrow “G” in FIG. 37. In thismanner, camming surfaces 360 a and 360 b travel over cam followersurfaces 350 e and 350 d, respectively, thereby urging lock spring 350downwardly in the direction of arrows “H” to overcome the spring forceof leaf spring portions 350 b and 350 c. This movement displacesproximal surface 350f below shoulder portion 332 a thereby permittingactuator rod 332 to move distally. Upon distal movement of actuator rod332 as indicated by arrow “I” in FIG. 38, a second shoulder portion 332b formed proximal of shoulder portion 332 a on actuator rod 332 contactsa rear wall portion 360 c of safety release slide 360 thereby urgingsafety release slide distally in a direction of arrow “I” as well. Uponrelease of actuator handle cover 246, actuator rod 332 moves proximallyas indicated by arrow “J” in FIG. 39 thereby permitting lock spring 350to move upwardly as indicated by arrow “K” in FIG. 39 to reset thefiring safety mechanism.

It will be understood that various modifications may be made to theembodiment shown herein. For example, the instruments may be sized toperform an anastomosis for other vessels and luminal tissue. Therefore,the above described should not be construed as limiting, but merely asexemplications of preferred embodiments. Those skilled in the art willenvision other modifications within the scope and spirit of the claimsappended hereto.

What is claimed is:
 1. A surgical instrument for performing ananastomosis, comprising: a housing having proximal and distal ends; ashaft extending from the distal end of the housing; a firing safetyassembly configured to prevent premature firing of the surgicalinstrument; a disposable loading unit configured for selectiveattachment to the shaft, the disposable loading unit including: afastener support member configured and dimensioned to support an arrayof surgical fasteners; a fastener pusher member being movable so as todeform the array of surgical fasteners; and a lock member configured toremovably engage the disposable loading unit relative to the shaft.
 2. Asurgical instrument for performing an anastomosis according to claim 1further comprising an actuator lever disposed on the housing whichcooperates with the fastener pusher member to form the array of surgicalfasteners.
 3. A surgical instrument for performing an anastomosisaccording to claim 1 wherein the disposable loading unit includesopposed split-sections being pivotable relative to one another betweenopen and closed configurations and movable through a firing stroke toform the array of surgical fasteners.
 4. A surgical instrument forperforming an anastomosis according to claim 3 further comprising anactuator lever disposed on the housing and operatively associated withthe opposed split sections such that movement of the actuator lever froman initial position to a second position effects movement of the opposedsplit sections to effect deformation of the array of surgical fasteners.5. A surgical instrument for performing an anastomosis according toclaim 3 wherein the disposable loading unit further includes a pivotlockout member which extends between the opposed split-sections toretain the opposed split-sections in the closed, non-pivotableconfiguration.
 6. A surgical instrument for performing an anastomosisaccording to claim 5 wherein the fastener pusher member is biased toreturn to a position proximate the fastener pusher member's initialposition after deformation of the surgical fasteners.
 7. A surgicalinstrument for performing an anastomosis according to claim 6 whereinupon return of the fastener pusher member to the position proximatefastener pusher member's initial position, the pivot lockout, member isdisplaced thus allowing the opposed split-sections to pivot relative toone another.
 8. A surgical instrument for performing an anastomosis,comprising: a housing having proximal and distal ends; an actuatormovable from an initial position to at least one second position; ashaft extending from the distal end of the housing; and a disposableloading unit configured for selective attachment to the shaft, thedisposable loading unit including: a fastener support member configuredand dimensioned to support an array of surgical fasteners in a partiallycompressed configuration; and a fastener pusher member being movable inresponse to movement of the actuator from the first to second positionsso as to deform the array of surgical fasteners.
 9. A surgicalinstrument for performing an anastomosis according to claim 8 whereinthe surgical fasteners include a traumatic, non-tissue penetrating ends.10. A surgical instrument for performing an anastomosis, comprising: ahousing having proximal and distal ends; an actuator movable from aninitial position to at least one second position; a shaft extending fromthe distal end of the housing; and a disposable loading unit configuredfor selective attachment to the shaft, the disposable loading unitincluding: a generally cylindrical anvil member; a fastener pushermember mounted with respect to the anvil member; and a plurality ofsurgical fasteners circumferentially disposed on the anvil member, thesurgical clips being partially compressed between the anvil member andthe fastener pusher member.